NdFeAsO1-d中凝聚粒子超电流连通性的证据
Evidence for Supercurrent Connectivity in Conglomerate Particles in NdFeAsO1-d
摘要：
在这里，我们使用全球和本地的磁强计和霍尔探针成像调查的电磁连通性的超导电流路径中的缺氧无氟钕基oxypnictides。高分辨率透射电子显微镜和扫描电子显微镜显示强层状微晶，单个颗粒周围存在约5 nm的无定形氧化物的证据，以及第二相氧化钕，这可能是高场和高温下大顺磁背景的原因。从全局磁力测量和电输运测量可以清楚地看出，在宏观样品尺寸（mm）上存在小的超电流流动，平均（在该长度尺度上）临界电流密度的下限为103 A/cm 2的量级。从粉末样品的磁力测量和单个大砾岩颗粒~120微米的局部霍尔探针成像可以清楚地看出，在较小的尺度上，存在更好的电流连通性，临界电流密度约为5 × 104 A/cm 2。我们发现增强磁通蠕变周围的第二个峰值异常的磁化曲线和不可逆线显着低于HC 2（T），由交流量热法确定。
英文摘要：
Here we use global and local magnetometry and Hall probe imaging to investigate the electromagnetic connectivity of the superconducting current path in the oxygen-deficient fluorine-free Nd-based oxypnictides. High resolution transmission electron microscopy and scanning electron microscopy show strongly-layered crystallites, evidence for a ~ 5nm amorphous oxide around individual particles, and second phase neodymium oxide which may be responsible for the large paramagnetic background at high field and at high temperatures. From global magnetometry and electrical transport measurements it is clear that there is a small supercurrent flowing on macroscopic sample dimensions (mm), with a lower bound for the average (over this length scale) critical current density of the order of 103 A/cm2. From magnetometry of powder samples and local Hall probe imaging of a single large conglomerate particle ~120 microns it is clear that on smaller scales, there is better current connectivity with a critical current density of the order of 5 x 104 A/cm2. We find enhanced flux creep around the second peak anomaly in the magnetisation curve and an irreversibility line significantly below Hc2(T) as determined by ac calorimetry.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
